Psychrometer



C. L. FORTIER -RSYC'HROMETER Jan. 14, 1930.

Filed-May 21, 1924 Charles Lifbr-fier;

abtouwgs Patented Jan. 14, 3923 9 CHARLES L. FORTIER, or MILWAUKEE, Wisconsin, Assreavon'ro Jot-insert snnvror.

COMPANY, or MILWAUKEE, WISCONSIN, A CORPORATION or WISCONSIN rsvonnomnrnn Application filed May 21,

This invention relates to psychrometers of the so-called sling type, and particularly to means for supplying water to the absorbent envelope which surrounds the bulb of the 5 wet bulb thermometer.

Sling psychrometers, as heretofore con structed, generally include a frame on which two thermometers and their graduated scales are mounted. This frame is provided with a 10 handle, or the like, about which it may be whirled. One thermometer, known as the wet bulb thermometer, is provided with an envelope of absorbent material such as China silk or linen fabric about its bulb. When the instrument is to be used, this envelope is dipped into or moistened with water, and the purpose of whirling the thermometers is to bring their bulbs, particularly the wet bulb, into contact with large volumes of air, so that the evaporation from the envelope may be accelerated.

In using psychrometers in dry atmospheres and at high temperatures incorrect readings are often caused by the fact-that the envelope dries out partly or completely, so that the correct wet bulb temperature is not recorded.

The present invention involves means for progressively supplying water to this envelope, while the device is in use, and in its preferred form involves also the construction of the device in such manner that centrifugal force assists the progressive feeding of water to the envelope.

A preferred embodiment of the invention is illustrated in the accompanying drawing in which:

Fig. 1 is a front elevation of the complete device; and

Fig. 2 is a View looking to the right relatively to Fig. 1. In this view part of the device is shown in section to illustrate the construction of the water reservoir.

In the drawing, 6 represents the handle in which is fixed a rod 7. Swiveled on the rod 7, by means of eyes or loops 8, is a plate 9 which serves as a supporting frame for the thermometers. The loops 8 are confined on the rod 7 between washers 10 by means of a cotter pin 11, and the frame 9 may be rotated on the shaft 7 by grasping the handle 6 in the 1924. Serial No. 714,949. 7

hand and giving the handle a rapid revolving motion. 7 1

Thermometers are mounted on'the frame 9 in the usual manner, each thermometer, being held in place by a clip 12, and being retained by an inturned nipple ortongue 13, which engages in a hole in the frame'9. I a I The dry bulb thermometer is shown at 1 1 and the wetbulb thermometer at 15. The graduated scales against which the mercury columns are read are preferably marked directly on the frame 9 as shown. of the thermometersla and 15 project beyond the lower or outer end of the framemember 9, so asto be subjected to free contact with the air. They are protected by projections l1)6 formed integrally with the frame mem- In order to providethe wet bulb thermometer 15 with a constantly moistened envelope, I

I mount fixedly in any suitable manner on the rear face of the frame 9 a reservoir 17, which extends from a point above the bulb of thermometer 15, i. e. from the point between the shaft 7 and said bulb to a point adjacent the bulb and preferably immediately below it.

A convenient form for the reservoir is the U-form, having unequal legs, shown in Fig. 2. The longer leg has a filling opening at its top which is normally closed by a cork 18. The shorter leg is open at its top 19 toreceive the pendent part of the linen or other envelope 20 surrounding the bulb of the thermometer 15.

The longer leg of the reservoir 17 is filled with an absorbent body 21, such as wicking, cotton wool, or the like, which is quite heavily saturated with distilled water and which isin contact with the envelope 20. When the device is at rest, water will feed by capillary attraction from the wicking 21 to the envelope 20. Consequently, the device maintains itself for considerable periods in condition for use.

When the device is being whirled, as described, centrifugal force tends to feed water downward through the absorbent body 21 and thus supplies water to the wicking 20 to replace that which evaporates. I have found.

that this arrangement greatly simplifies the The bulbs securing of accurate wet bulb readings and thus facilitates successful use of the device.

Obviously, the invention may be expressed in various specifically different structures. I do not limit myself to the exact construction shown and described as others will readily suggest themselves to those skilled in the art.

vVhat is claimed is:

1. A psychrometer of the sling type including two thermometers; a moisture absorbing envelope surrounding the bulb of one of said thermometers; means for whirling said thermometers through the air; a porous water-carrying unit mounted to whirl with said thermometers and arranged to supply Water to said envelope While said thermometers are being whirled.

2. A psychrometer of the sling type in cluding two thermometers, one of which has a moisture absorbing envelope; means for whirling said thermometers through the air;

a Water-charged unit in contact with said envelope and adapted to feed Water thereto while said thermometers are being whirled.

3. A psychrometer of the sling type including two thermometers, one of w iich has a moisture absorbing envelope; means for whirling said thermometers through the air; and a chamber containing a water carrying unit located nearer the axis of whirling than said envelope, and arranged. to feed water to said envelope by centrifugal force while the instrument is being whirled.

In testimony whereof I have signed my name to this specification.

CHARLES L. FORTIER. 

